I couldn't get the mouse sprite to overlay the cursor (pc mouse) so, the pc mouse is the mouse. the cat goes fast so, watch out. it isn't very sophisticated. you just move the mouse to avoid the cat if the cat gets to the mouse, the cat gets a point. try to keep the cat's score at 0. it's pretty hard.
the scratch help cards gave me the idea. they have an example of a shark chasing a fish and a cat chasing the mouse so, I basically just copied the example.